1. Field of the Invention
This invention pertains to warehousing techniques and to retractable chain link lifting devices.
2. Description of the Prior Art
Heretofore the customary warehousing technique for palletized or otherwise vertically separated objects is to either pigeon-hole the objects in vertical shelves or stack the palletized objects on one another in vertical rows. In both instances, the aisles separating the rows must be wide enough to provide access for a forklift or a conveying mechanism having forklift arms so that the forklift arms can remove an object and pass with it through the aisle to a discharge station. The forklift arms in these prior art devices of necessity require an aisle width wide enough to handle the object. In some cases, extra room is even provided in the aisle so that the forklift truck can turn 90.degree. to transport the object down the aisle. In a typical illustration, an aisle 6 foot in width is customarily employed for handling objects only 4 feet in depth. As a result of these handling techniques as much of the warehouse space is consumed by the aisle width as is storage space and increases the expense necessary for storing objects.
As mentioned above, conventional forklifts employ solid arms which require an aisle width at least as great as the object under which the arms are to be inserted. Some attempts have been made to provide completely retractable fork lift arms however none has been successful. Examples of such devices are shown in U.S. Pat. Nos. 3,709,394 and 2,574,045. Other retractable chain link devices, such as booms, are also generally not satisfactory for forklift operations since the chains are retracted into a coil having a substantial, horizontal diameter and thus consumed almost as much space as solid telescopic forklift arms. Furthermore, known chain link booms are expensive to manufacture, complicated to operate and maintain, and are difficult to modify to increase or vary their lifting capacity.